An unpleasant phenomenon after vestibular schwannoma surgery: Delayed facial palsy

Facial palsy is a functional disability and a cosmetic distress for patients who undergo vestibular schwannoma surgery. The aim of modern schwannoma surgery is not only complete tumor removal but preservation of the seventh and eighth nerve complex. With microsurgical techniques and intraoperative cranial nerve monitoring, preservation can be achieved in most cases. Nevertheless, preservation of the anatomic integrity of the facial nerve does not always predict the outcome of postoperative facial function. In addition to structural preservation of the nerve itself, other factors influencing facial function need to be considered. Delayed facial palsy disappoints the surgeon as well as the patient when it occurs hours or days after surgery. The etiology is complicated and poorly understood; thus, the treatment strategies vary. Many hypotheses have been postulated, including intraoperative manipulation, vascular compromise, an edematous process, external compression, and viral reactivation in the facial nerve. Without histologic or electrophysiologic confirmation, the cause of delayed facial palsy remains speculative. We suggest that postoperative vasospasm in combination with edema of the nerve may explain this unpleasant phenomenon and review the literature to discuss the other possible etiologies of this disease entity. Some strategies are also proposed to treat and prevent its occurrence.